Revolute

Represent assembled revolute joint with one rotational degree of freedom

Library

Joints

Description

The Revolute block represents a single rotational degrees of freedom (DoF) about a specified axis between two bodies. The rotational sense is defined by the right-hand rule. A revolute joint is one of SimMechanics™ primitive joints, along with prismatic and spherical.

The Revolute block is assembled: you must connect each side of the Joint block to a Body block at a Body coordinate system (CS) point, and the origins of these Body CSs must be spatially collocated points, to within assembly tolerances.

You must connect any Joint block to two and only two Body blocks, and Joints have a default of two connector ports for connecting to base and follower Bodies.

A Joint block represents only the abstract relative motion of two bodies, not the bodies themselves. You must specify a reference CS to define the direction of the joint axis.

Revolute Motion of Follower (blue) Relative to Base (red)

Dialog Box and Parameters

The dialog has two active areas, Connection parameters and Parameters.

Connection Parameters

The base (B)-follower (F) Body sequence determines the sense of positive motion. Positive rotation is the follower rotating in the right-hand rule about the rotation axis.

Current base

When you connect the base (B) connector port on the Revolute block to a Body CS Port on a Body, this parameter is automatically reset to the name of this Body CS. See the following figure, Revolute Base and Follower Body Connector Ports.

Current follower

When you connect the follower (F) connector port on the Revolute block to a Body CS Port on a Body, this parameter is automatically reset to the name of this Body CS. See the following figure, Revolute Base and Follower Body Connector Ports.

Number of sensor/actuator ports

Using this spinner menu, you can set the number of extra connector ports needed for connecting Joint Actuator and Joint Sensor blocks to this Joint. The default is 0.

The motion of a Revolute is specified in angular units.

Revolute Base and Follower Body Connector Ports

Parameters

Toggle between the Axes and Advanced panels with the tabs.

The entries on the Axes pane are required. They specify the direction of the rotation axis of the DoF that the Revolute represents.

Name

This column automatically displays the name of each primitive joint contained in the Joint block. For Revolute, there is only one primitive joint, a revolute, labeled R1.

Primitive

This column automatically displays the type of each primitive joint contained in the Joint block. For Revolute, there is only one primitive type, labeled Revolute.

Axis of rotation [x y z]

Enter here as a three-component vector the directional axis about which this rotational DoF can move. The default vector is [0 0 1]. The axis is a directed vector whose overall sign matters.

Reference CS

Using the pull-down menu, choose the coordinate system (World, the base Body CS, or the follower Body CS) whose coordinate axes the vector axis of rotation is oriented with respect to. This CS also determines the absolute meaning of torque and motion about the joint axis. The default is World.

The Advanced pane is optional. You use it to control the way SimMechanics simulation interprets the topology of your schematic diagram.

Mark as the preferred cut joint

In a closed loop, the simulation internally and automatically cuts one and only one joint.

If you want this particular joint to be weighted preferentially for cutting during the simulation, select the check box. The default is not selected.

 Restricted Parameters

See Also

Disassembled Revolute, Joint Actuator, Joint Initial Condition Actuator, Joint Sensor, Joint Stiction Actuator, Prismatic, Spherical

See Modeling Degrees of Freedom for more on representing DoFs with Joints.

See Verifying Machine Topology and How SimMechanics™ Software Works for more on closed loops and cutting.

  


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